In general, as shown in FIG. 1, an air conditioner system for a vehicle has a refrigeration cycle that includes: a compressor 1 for compressing and discharging refrigerant; a condenser 2 for condensing the refrigerant of high pressure discharged from the compressor 1; an expansion valve 3 for throttling the refrigerant condensed and liquefied in the condenser 2; and an evaporator 4 for exchanging heat between the liquefied refrigerant of low pressure throttled by the expansion valve 3 and air blown to the interior of the vehicle and evaporating the refrigerant to cool the air discharged to the interior of the vehicle due to heat absorption by evaporative latent heat, and that the compressor 1, the condenser 2, the expansion valve 3 and the evaporator 4 are connected with each other via refrigeration pipes. The air conditioner system cools the interior of the vehicle through the following refrigerant circulation process.
When a cooling switch (not shown) of the air conditioner system is turned on, first, the compressor 1 inhales and compresses gas-phase refrigerant of low-temperature and low-pressure while driving by driving power of an engine or a motor, and then sends the refrigerant in the gaseous phase of high-temperature and high-pressure to the condenser 2. Then, the condenser 2 condenses the gas-phase refrigerant into liquid-phase refrigerant of high-temperature and high-pressure by exchanging heat with outdoor air. After that, the liquid-phase refrigerant of high-temperature and high-pressure sent from the condenser 2 rapidly expands by a throttling action of the expansion valve 3 and is sent to the evaporator 4 in a wet-saturated state of low-temperature and low-pressure. The evaporator 4 exchanges heat between the refrigerant and air blown to the interior of the vehicle by a blower (not shown). Then, the refrigerant is evaporated in the evaporator 4 and discharged in a gaseous phase of low-temperature and low-pressure. After that, the gas-phase refrigerant is inhaled into the compressor 1, and then, recirculates the refrigeration cycle as described above.
In the refrigerant circulation process, as described above, the air blown by the blower (not shown) is cooled by evaporative latent heat of the liquid-phase refrigerant circulating inside the evaporator 4 and discharged to the interior of the vehicle in a cooled state so as to cool the interior of the vehicle.
Meanwhile, the condenser 2 which is an air-cooled condenser is mounted at the front side of the vehicle to cool the refrigerant using traveling wind from the front of the vehicle.
However, if the air-cooled condenser is mounted at the front side of the vehicle, a cooling module package mounted at the front side of the vehicle becomes excessively bigger. Moreover, when the vehicle idles, because air of high-temperature in an engine room flows backward toward the front side of the vehicle and is induced into the air-cooled condenser, temperature of the air induced into the air-cooled condenser gets higher, and it causes deterioration in air-conditioning performance.
Recently, in order to enhance air-conditioning performance, a water-cooled condenser 20 and an internal heat exchanger 25 are applied to an air conditioner system. Referring to FIG. 2, the water-cooled condenser 20 heat-exchanges the refrigerant discharged to the compressor 1 with coolant to condense the refrigerant.
That is, coolant circulating inside a water-cooled radiator 50 mounted in an engine room of the vehicle is supplied into the water-cooled condenser 20 and exchanges heat with the gas-phase refrigerant discharged from the compressor 1, so that the gas-phase refrigerant is cooled and condensed to be changed into a liquid-phase refrigerant.
The water-cooled radiator 50 exchanges heat between the coolant flowing inside the water-cooled radiator 50 and the air by a water pump (WP) to cool electronic units of the vehicle, such as a battery, an inverter, a motor and so on.
Moreover, the internal heat exchanger 25 exchanges heat between the refrigerant discharged from the water-cooled condenser 20 and the refrigerant discharged from the evaporator 4.
Therefore, the refrigerant discharged from the water-cooled condenser 20 enhances air-conditioning performance through supercooling because being further cooled in the internal heat exchanger 25 and flowing to the expansion valve 3.
In the meantime, a receiver drier 30 which separates the refrigerant passing through the water-cooled condenser 20 into gas-phase refrigerant and liquid-phase refrigerant is mounted.
Furthermore, not shown in the drawings, but, the water-cooled condenser 20 is partitioned into a condensing region and a supercooling region through a baffle (not shown). In this instance, the refrigerant passing through the condensing region of the water-cooled condenser 20 is induced into the receiver drier 30, and the refrigerant induced into the receiver drier 30 flows to the supercooling region of the water-cooled condenser 20 to be supercooled, and then, is induced into the internal heat exchanger 25.
However, in the conventional air conditioner system, when the vehicle idles or when the outdoor temperature rises, temperature of the coolant passing the water-cooled radiator 50 also rises. In this instance, when temperature of the coolant rises, temperature of the refrigerant of the water-cooled condenser 20 which exchanges heat with the coolant also rises so that the refrigerant is induced into the internal heat exchanger 25. After that, the refrigerant is induced into the expansion valve 3 and the evaporator 4, and it causes deterioration in air-conditioning performance.
Additionally, due to the limit of the outdoor temperature which cools the coolant of the water-cooled radiator 50, temperature of the coolant of the water-cooled radiator 50 is high and the water-cooled condenser 20 does not provide sufficient condensation in the condensing region, and hence, gas-liquid separation is not achieved smoothly in the receiver drier 30 due to high quality of the refrigerant induced into the receiver drier 30. Finally, because not only the liquid-phase refrigerant but also the gas-phase refrigerant are induced to the supercooling region of the water-cooled condenser 20, the receiver drier 30 cannot carry out its performance well.
In addition, because the water-cooled condenser 20, the receiver drier 30 and the internal heat exchanger 25 are arranged disorderedly, the package becomes excessively bigger and it is not easy to mount them inside the engine room of the vehicle.